Low noise amplifiers (LNA) are commonly used in front end receivers. An LNA is designed to have certain properties, such as an input resistance that matches an antenna, a certain gain (e.g., 10 to 20 dB), low noise, good linearity, etc. Front end receivers also have a mixer that mixes a received signal with an oscillating signal. A current commuting mixer inputs a current, whereas an LNA outputs a voltage. To convert from voltage to current, some front end receivers use transconductors between the LNA and mixer. Although transconductors have their advantages, one disadvantage to using a transconductor is that it consumes power since transconductors include transistors which must be biased. Also, the transconductor must be designed so that certain properties (e.g., linearity) are acceptable. It would be desirable if new LNA circuits could be designed that consume less power and/or and have better linearity. Furthermore, it would be desirable if these LNA circuits were broadband and/or could be configured to operate at a selected frequency of interest.